E291 🟡 Repair Required
Navien Error Code E291: Cascade Communication Error
⚠️ Your Navien boiler's cascade communication is experiencing an error, which may impact its performance and efficiency. It's safe to troubleshoot, but if the issue persists, contact a professional.
How to Fix Navien Code E291
- Check if the cascade module is securely connected and powered
- Ensure the module's configuration matches your boiler's settings
- If the issue persists, try resetting the boiler and the cascade module
What Does Navien Error Code E291 Mean?
The E291 error on your Navien boiler indicates a cascade communication issue between the boiler and its optional cascade module. This error doesn't pose an immediate safety risk, but it's important to address it to maintain optimal system performance. The cascade module allows multiple boilers to operate together, and this error suggests there's a problem with this communication.
Common Causes of Navien Code E291
- Faulty cascade module or wiring
- Incorrect configuration or settings
- Power supply issue with the cascade module
- Interference from other electrical devices
Applicable Navien Models
Source Documentation
This error code is documented in 3 official Navien technical manuals.
NFB-H Installation & Operation ManualPage 116
ReasonReturn Temp. Exceeds Supply
ActionCheck for reversed piping.
Navien NFB-H Installation & Operation ManualPage 116
ReasonReturn Temp. Exceeds Supply
ActionCheck for reversed piping.
Navien NHB-H Installation & Operation ManualPage 119
ReasonReturn Temp. Exceeds Supply
ActionCheck for reversed piping.
Need a Pro to Fix Navien Code E291?
A licensed HVAC technician can diagnose and fix this issue quickly.
Find a Licensed Tech Near You →Replacement Parts for Navien Tankless Water Heater Code E291
Cascade Module OEM: NAVIEN-01C000000-00